Foot Progression Angle Modulates Knee Loading During Walking in Individuals with Flexible Flatfoot.

Portable, automated foot progression angle gait modification via a proof-of-concept haptic feedback-sensorized shoe

This study aims to investigate the effects of knee and foot alignments on the risk of falling. Between April 2016 and December 2016, a total of 74 individuals (24 males, 50 females; mean age 32.2±4.9 years; range 18 to 65 years) were included in the study. The knee Q angle and Chippaux-Smirak Index (CSI), Arch Index, and foot progression angle (FPA) evaluated by pedobarography were used for the assessment of the lower extremity alignment. The fall risk was evaluated by the Fall Index, Fourier 56 Index (F56), and Stability Index. The fall index was found to be correlated with the Q angle, CSI, the Arch index, and FPA (p<0.05). Q angle, Arch Index, and FPA which were explained 40% of the variance of the fall index. The Q angle was correlated with F56 and the stability index at the most position (p<0.05). The CSI was correlated with the F56 and the stability index at two and three positions, respectively (p<0.05); however, the Arch Index and FPA were not correlated with the F56 and Stability Index at any of the eight positions (p>0.05). According to the categorical regression analysis, the Q angle was the most effective on the F56 and Stability Index. Our study results suggest that lower extremity malalignment increases the risk of falling. We believe that the risk of falling can be decreased by the reduction of these malalingments and, thus, mortality and morbidity associated with the fall can be reduced as well.

The mechanical loads placed on the knee during gait, in particular the adduction moment (KAM), have been implicated in the progression of knee osteoarthritis (OA). Those presenting with symptomatic medial compartment knee OA tend to adopt a toe out gait pattern reducing the peak KAM during gait, hence unloading the diseased medial compartment. Although this is known, the relationship between the foot progression angle (FPA) and the KAM, along with other knee gait kinetic measures has yet to be determined. PURPOSE To determine the relationship between FPA and 3D knee gait forces and moments. METHODS Gait analysis was performed on 11 healthy subjects (23 +/− 1.7 yrs). Subjects performed five trials in each of three conditions: natural foot position (NFP), approximately 30 degrees internally rotated (IR) and approximately 30 degrees externally rotated (ER) from their natural position. 3D knee joint forces and moments were compared to true FPA (ANOVA) and a regression analysis determined the relationships between normalized (by NFP) values. RESULTS Late stance peak KAM and medial-lateral shear forces (MLF) were significantly different across conditions, (KAM: ER=0.125, NFP=0.267, IR=0.410 Nm/kg; p<0.01 and MLF: ER=−0.980, NFP=−1.248, IR=−1.447 N/kg; p<0.01). See Figure 1 for average gait curves. There were also strong relationships between changes in FPA (actual range of 49.3 ±) and changes in KAM (R2=.97) and MLF (R2=.88).FigureCONCLUSIONS Results suggest that for every 10 degree change in FPA there is a 21.7% change in KAM and a 7.6% change in MLF during late stance. This may have implications in preventing the development and progression of knee OA.

Trunk lean and toe out gait strategies impact on lower limb joints

Background: Rotational profiles vary widely among healthy children. Rotation of the long bones refers to the twist of the bone about its long axis. Rotational deformity of the lower limb in the transverse plane is associated with many clinical settings ranging from harmless to excessive intoeing in children. Materials and Methods: This study was conducted at the Department of Orthopedics, Indraprastha Apollo Hospital, New Delhi. Children presenting to the outpatient department during the period of April to September 2013 were followed up. It is a prospective study conducted over 14 months. A total of 27 children (54 lower limbs) were included and followed up. Results: Twenty-seven children were selected as per the inclusion criteria and assessed for the thigh-transmalleolar axis, thigh-foot angle, femoral anteversion (FA), foot progression angles (FPA), and hip rotations at 4-month interval for 2 follow-ups. There were very few studies of such type which have been conducted in India. Conclusions: In our study, there was a definite and significant decrease in FPA and internal tibial torsion with increasing age. The values of clinical anteversion also decreased with age along with a gradual decrease of internal rotation and an increase of external rotation (ER). The decrease of FA with age correlated better with increase of hip ER. FPA was a significant clinical parameter which gave us an objective picture of the change in both femoral and tibial torsions with age.

Stride length (SL), foot clearance (FC), and foot progression angle (FPA) are the key parameters for diagnosing gait disorders. This study used the distance data between two feet measured by ultra-wideband (UWB) sensors installed on shoes and proposed a method for estimating the three gait parameters. Here, a method of compensating the offset of the UWB sensor and estimating the distances between a base sensor installed on one foot during the stance phase and three UWB sensors on the other during the swing phase was applied. Foot trajectory was acquired in a gait experiment with ten healthy adults walking on a treadmill. The results were compared with those obtained using a motion capture system (MCS). The UWBs sensor displayed average errors of 45.84 mm, 7.60 mm, and 2.82° for SL, FC, and FPA, respectively, compared with the MCS. A similar accuracy level was achieved in a previous study that used an inertial measurement unit (IMU). Thus, these results suggest that UWB sensors can be extensively applied to sensor systems used to analyze mobile gait systems.

The determination of rotation of the femur during intramedullary nailing procedures can be difficult, particularly when the fracture pattern does not lend itself to interdigitation. We studied 22 patients who had isolated femur fractures treated by closed intramedullary nailing to determine the degree of malrotation introduced at the time of surgery. Anteversion of the affected and normal femora was determined by a standard computed tomography (CT) torsion study. The range of motion of the hip was measured in the prone position. Foot progression angles (FPAs) were measured in 14 patients who were fully ambulatory for at least 6 months. The average malrotation of the fractured femur was 16 degrees (4 to 61 degrees). The median malrotation was 14 degrees. The differences in CT-measured anteversion (delta A), FPA (delta FPA), internal rotation (delta IR), and external rotation (delta ER) between the affected and normal sides were determined. Linear regression was used to analyze delta A with delta FPA, delta IR, and delta ER. Changes in internal and external rotation as determined by physical exam had a stronger correlation with delta A than did delta FPA. This indicates that malrotation of the femur is accommodated for during gait. Based on this data, we found that anteversion of the normal femur can be determined in the operating room using the image intensifier and can be duplicated on the fractured side using the described technique in cases where comminution prevents fragmentational alignment. This method has been used for 12 patients in a prospective trial, and malrotation has been kept to under 10 degrees in all cases.

The purpose of this study is to determine the tibiofemoral forces during functional electrical stimulation (FES) rowing in individuals with spinal cord injury (SCI). We analysed the motion of five participants with SCI during FES rowing, with simultaneous measurements of (i) three-dimensional marker trajectories, (ii) foot reaction forces (FRFs), (iii) ergometer handle forces, and (iv) timestamps for electrical stimulation of the quadriceps and hamstrings muscles. We created full-body musculoskeletal models in OpenSim to determine subject-specific tibiofemoral forces during FES rowing. The peak magnitudes of tibiofemoral forces averaged over five participants with SCI were 2.43 ± 0.39 BW and 2.25 ± 0.71 BW for the left and right legs, respectively. The peak magnitudes of FRFs were 0.19 ± 0.04 BW in each leg. The peak magnitude of handle forces was 0.47 ± 0.19 BW. Peak tibiofemoral force was associated with peak FRF (magnitudes, R2 = 0.56, p = 0.013) and peak handle force (magnitudes, R2 = 0.54, p = 0.016). The ratios of peak magnitude of tibiofemoral force to peak magnitude of FRF were 12.9 ± 1.9 (left) and 11.6 ± 2.4 (right), and to peak magnitude of handle force were 5.7 ± 2.3 (left) and 4.9 ± 0.9 (right). This work lays the foundation for developing a direct exercise intensity metric for bone mechanical stimulus at the knee during rehabilitation exercises. Clinical Significance: Knowledge of tibiofemoral forces from exercises such as FES rowing may provide clinicians the ability to personalize rehabilitation protocols to ensure that an SCI patient is receiving the minimum dose of mechanical stimulus necessary to maintain bone health.

PurposeThe changes in the lower limb alignment were vitally important after high tibial osteotomy (HTO). Therefore, the purpose of present study was to analyze the characteristics of plantar pressure distribution after HTO, and to investigate the effect of plantar pressure distribution on postoperative limb alignment.MethodsBetween May 2020 and April 2021, varus knee patients undergoing HTO were evaluated in the present study. The peak pressure of plantar regions, medial-lateral pressure ratio (MLPR), foot progression angle (FTA), anteroposterior COP (AP-COP), lateral symmetry of COP (LS-COP), and the radiographic parameters were evaluated preoperatively and at the final follow-up. Compared among the slight valgus (SV), moderate valgus (MV) and large valgus (LV) groups at the final follow-up, the peak pressure of HM, HC and M5 regions, and the MLPR were compared; the Knee Injury and Osteoarthritis Outcome Score4 (KOOS4) including four subscales, and the American of orthopedic foot and ankle society (AOFAS) were evaluated.ResultsThe WBL%, HKA and TPI angle changed significantly after HTO (P < 0.001). The preoperative group exhibited a lower peak pressure in the HM region (P < 0.05) and higher peak pressure in the M5 region (P < 0.05); the pre- and postoperative groups exhibited a lower peak pressure in the HC region (P < 0.05); the rearfoot MLPR was significantly lower and LS-COP was significantly higher in the preoperative group (P = 0.017 in MLPR and 0.031 in LS-COP, respectively). Comparison among the SV, MV and LV groups, the SV group indicated a lower peak pressure in the HM region (P = 0.036), and a lower MLPR in the rearfoot (P = 0.033). The KOOS Sport/Re score in the MV and LV groups increased significantly compared with the SV group (P = 0.042).ConclusionPlantar pressure distribution during the stance phase in patients with varus knee OA following HTO exhibited a more medialized rearfoot plantar pressure distribution pattern than that before surgery. Compared with the small valgus alignment, a moderate to large valgus alignment allows patients to walk with a more even medial and lateral plantar pressure distribution, which is more similar to healthy adults.

Ankylosing Spondylitis (AS) is an inflammatory chronic disease that causes postural changes. As a result of these changes decreased hip flexion, increased knee flexion and plantar flexion of ankle are developed. The aim of the study is to compare plantar pressure distribution results in patients with AS and healthy individuals and to determine the relationship between clinical and functional parameters in patients with AS. Twenty-five patients (median age = 42.2 ± 2.1years) with AS and 25 healthy individuals (median age = 44.4 ± 1.7years) were included in the study. The maximum foot pressure (FPmax), average pressure, center of pressure angle (CoP),forefoot load (FFL), rearfoot load (RFL), foot progression angle (FPA) and foot angle (FA) weredetermined by pedobarographic analysis. Spinal mobility was assessed with lumbar flexion, lateral flexion, and tragus-wall distance. Functional status and disease-related symptoms were assessed with BASDAI, BASFI and ASQoL. There were no differences between static and dynamic pedobarographic analysis parameters between the AS group and the control group (p > 0.05). Self-rated functional levels parameters, pain, and stiffness were higher in the AS group (p < 0.05). Lumbar flexion (p = 0.187) and tragus-to-wall distance (p = 0.196) were similar in two groups. Self-rated parameters were correlated with pain, stiffness, and lateral flexion (p < 0.05). Lateral flexion correlated with FA and FFL; tragus to wall distance correlated with FPmax and CoP and RFL; lumbar flexion correlated with FA (p < 0.05). The results showed that there was no difference plantar pressure distribution but there was a difference in spinal mobility in AS group compared healthy individuals.

A cost-effective gait analysis system without attachments and specialized large environments can provide useful information to determine effective treatment in clinical sites. This study investigates the capability of a single camera-based pose estimation system using OpenPose (OP) to measure the temporo-spatial and joint kinematics parameters during gait with orthosis. Eleven healthy adult males walked under different conditions of speed and foot progression angle (FPA). Temporo-spatial and joint kinematics parameters were measured using a single camera-based system with OP and a three-dimensional motion capture system. The limit of agreement, mean absolute error, absolute agreement (ICC2, 1), and relative consistency (ICC3, 1) between the systems under each condition were assessed for reliability and validity. The results demonstrated that most of the ICC for temporo-spatial parameters and hip and knee kinematics parameters were good to excellent (0.60 - 0.98). Conversely, most of the ICC for ankle kinematics in all conditions were poor to fair (< 0.60). Thus, the gait analysis using OP can be used as a clinical assessment tool for determining the temporo-spatial, hip, and knee sagittal plane angles during gait.

To elucidate the correlating factors and clinical significance of flexible flatfoot (FF) in preschool children of Taiwan, a cross-sectional study was conducted in a research laboratory equipped with a gait analysis facility. Altogether, 377 preschool children (201 boys, 176 girls), ranging in age from 2 to 6 years, were enrolled in this investigation. The results show that age, height, weight, foot progression angle, occurrence of physical knock-knee, and joint laxity score correlate with FF. Children with FF, compared with children without, performed physical tasks poorly and walked slowly, as determined by gait parameters. The FF should not simply be regarded as a problem of static alignment of the ankle and foot complex, but may be the consequence of a dynamic functional change of the lower extremity. Better understanding of the correlating factors and the clinical relevance of FF may prove helpful in deciding on the most appropriate treatment for a particular patient.

Purpose: This study examined the effects of flexible flatfeet on the accuracy of knee joint motions in closed and open kinetic chain tasks. Methods: Twenty-four healthy participants were recruited for this study. The subjects were divided into two groups using a navicular drop (ND) test: flexible flatfoot group (n=12, male: 6, aged 22.00±2.22 years) and age-matched control group (n=12, males: 6, aged 22.17±1.53 years). The accuracy of knee motion was measured quantitatively by tracing through the flexion and extension motion of the knee joints in the closed kinetic chain and the open kinetic chain. Results: There was a significant difference in the accuracy index between the groups in closed kinetic chain task, but there was no significant difference in the open kinetic chain task. In addition, there was a significant difference in the accuracy index between the closed kinetic chain and the open kinetic chain task in the flexible flatfoot group. In addition, a significant negative correlation was observed between the ND and accuracy index in the closed kinematic chain task, but there was no significant relationship between the ND and accuracy index in the open kinematic chain task. Conclusion: Flexible flatfeet can affect the accuracy of the adjacent joints, such as the knee joint in the closed kinematic chain.

One of the main causes that make knee osteoarthritis (OA) worse is load concentration at the medial compartment of knee cartilage. It is alternatively measured by employing knee adduction moment (KAM). Since toe-in gait decreases the 1st peak of KAM, it has been considered as a non-surgical prevention of OA progressing. However, direct measures such as contact pressure at knee cartilage in motion have not been available so far. Obtaining contact pressure at knee cartilage by FE analysis is difficult because exact muscle forces are not available and because FE model should be reconstructed at every stance phase. To obtain contact pressure at knee cartilage during gait, a method employing FE analysis based on motion analysis has been used in this study. Reference FE model of lower extremities was constructed and transformed to specific stance phases of gait. Ground reaction forces and muscle forces from motion analysis were employed as loading conditions. Finally, contact pressure distributions on knee cartilage at 1st peak, mid stance, 2nd peak could be obtained with respect to foot progression angle. The result shows that toe-in gait could be effective for knee OA patients by dispersing contact pressure concentrated in medial knee compartment to lateral part.

Cartilage is responsive to the loading imposed during cyclic routine activities. However, the local relation between cartilage in terms of thickness distribution and biochemical composition and the local contact pressure during walking has not been established. The objective of this study was to evaluate the relation between cartilage thickness, proteoglycan and collagen concentration in the knee joint and knee loading in terms of contact forces and pressure during walking. 3D gait analysis and MRI (3D-FSE, T1ρ relaxation time and T2 relaxation time sequence) of fifteen healthy subjects were acquired. Experimental gait data was processed using musculoskeletal modeling to calculate the contact forces, impulses and pressure distribution in the tibiofemoral joint. Correlates to local cartilage thickness and mean T1ρ and T2 relaxation times of the weight-bearing area of the femoral condyles were examined. Local thickness was significantly correlated with local pressure: medial thickness was correlated with medial condyle contact pressure and contact force, and lateral condyle thickness was correlated with lateral condyle contact pressure and contact force during stance. Furthermore, average T1ρ and T2 relaxation time correlated significantly with the peak contact forces and impulses. Increased T1ρ relaxation time correlated with increased shear loading, decreased T1ρ and T2 relaxation time correlated with increased compressive forces and pressures. Thicker cartilage was correlated with higher condylar loading during walking, suggesting that cartilage thickness is increased in those areas experiencing higher loading during a cyclic activity such as gait. Furthermore, the proteoglycan and collagen concentration and orientation derived from T1ρ and T2 relaxation measures were related to loading.